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authorAlexei Starovoitov <ast@fb.com>2017-05-30 23:31:35 +0300
committerDavid S. Miller <davem@davemloft.net>2017-06-01 02:29:48 +0300
commit2960ae48c4636778761610dd49187691c3774465 (patch)
tree7578aae05af40cd063fa3cd8679effc13a28863b
parent177366bf7ceb35860281a6ebe824e42bf96fd95d (diff)
downloadlinux-2960ae48c4636778761610dd49187691c3774465.tar.xz
bpf: take advantage of stack_depth tracking in x64 JIT
Take advantage of stack_depth tracking in x64 JIT. Round up allocated stack by 8 bytes to make sure it stays aligned for functions called from JITed bpf program. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/x86/net/bpf_jit_comp.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index c96dac838f3e..617eac9c4511 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -206,7 +206,7 @@ struct jit_context {
/* emit x64 prologue code for BPF program and check it's size.
* bpf_tail_call helper will skip it while jumping into another program
*/
-static void emit_prologue(u8 **pprog)
+static void emit_prologue(u8 **pprog, u32 stack_depth)
{
u8 *prog = *pprog;
int cnt = 0;
@@ -214,8 +214,9 @@ static void emit_prologue(u8 **pprog)
EMIT1(0x55); /* push rbp */
EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
- /* sub rsp, MAX_BPF_STACK + AUX_STACK_SPACE */
- EMIT3_off32(0x48, 0x81, 0xEC, MAX_BPF_STACK + AUX_STACK_SPACE);
+ /* sub rsp, rounded_stack_depth + AUX_STACK_SPACE */
+ EMIT3_off32(0x48, 0x81, 0xEC,
+ round_up(stack_depth, 8) + AUX_STACK_SPACE);
/* sub rbp, AUX_STACK_SPACE */
EMIT4(0x48, 0x83, 0xED, AUX_STACK_SPACE);
@@ -363,7 +364,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
int proglen = 0;
u8 *prog = temp;
- emit_prologue(&prog);
+ emit_prologue(&prog, bpf_prog->aux->stack_depth);
if (seen_ld_abs)
emit_load_skb_data_hlen(&prog);